IH84.] SPECIES OF OREASTER. HI 



general granulation of which is rather delicate. In the adult the 

 shield-shaped madreporic plate is covered with granules. 



Colour (in spirit) creamy white or white. 



Measurements : — 



The two specimens whose admeasurements are marked with an 

 asterisk were determined by M. Perrier as examples of his species 

 N. michelini ; but there can hardly be any doubt that within the 

 limits of a millimetre or two diflferences may always obtain in the 

 development of defensive spines, and the two species may well be 

 united. 



Hab. W. coast Central America ; Sandwich Islands. 



Oreaster westermanm. 



Oreaster westenimnni, Liitken, Vidensk. Med, 1871, p. 264. 



" Dorsum deplauatumfere, brachia longissima, radio stellce majore 

 minorem triphim quinta parte superante ; tessellte marginales 

 admodum convexce, alternantes c. 30 ; dorsvales, luberculis 1—4 

 minutis obsittv, solce (apice brachiorum excepta) ipsum marginem 

 stellte formant ; arece poriferce triangulares, scppe confluentes^ 

 poris numcrosissimis ; tubercuJa numerosissima mediocria obiusa 

 in nodis trabecularum, in parte centrali stellfe et basuli brachi- 

 orum conica vel cylindrica fere, in parte terminali brachiorum 

 crassiora, convexa, approximata, iessellasque marginales fere 

 teguantia, series quinas in brachiis formant, media c. 30 nvme- 

 rante ; tubercvla 5 dvplicia paullo modo majora et parum inter 

 cetera conspicua partem centralem stellts circumdant ; tessellee 

 venlrulcs proprice tuber culiformes, minutee, numerosce, pi-opler 

 granula obtegentia liuud conspicuce, prceter granula singulam 

 {prope ambulacra duplicem vel tripUcem) spinam crassam ob- 

 tusam gerunt ; papilhe ambvlacrales triserialte, internre nonce, 

 graciles, ceteree crassoe, obtusce, ternce (rarius bince vel quaterna;); 

 pedicellarice valvulafte minutce rarcB prope ambulacra. Hab. ad 

 oras Bengaliae." 



Oreaster superbiis. 



Oreaster supeibus, Miibius, Neue Seesterne, p. 5; Abh. Geb. 

 Naturw. Hamburg, Bd. iv. Abth. ii. 



The figures of Mobius show that this is a really remarkable species, 

 on account of the knobbed character of its spines, and the ap- 

 parently restricted size of the poriferous areas. 



It would seem that R is about equal to 4 r ; the lophial line 

 distinguished by the presence of knobbed processes, somewhat 

 irregularly, but always closely, arranged. Some of the more 

 proximal superomarginals bear knobbed spines, and the inferor 

 marginals till about the middle of the arm have two, whereof the 



Proc. Zool. Soc— 1884. No. VI. 6 



